You see people in the gym doing thousands of sit ups and planking for hours (well maybe not hours, but sometimes it feels like it). This is traditionally the way that people have learned to train the "core" muscles. While there's nothing inherently wrong with either of these movements, they just aren't the most effective way to do it. Also, the core is made up of more than just your rectus abdominals that is traditionally considered the six pack. Let's talk about the other muscles that make up the core and how we train them.
What muscles make up the core?
The core is comprised of all the muscles that surround your trunk. From the front of your abdomen to your low back, these muscles work together to create a rigid trunk for transferring forces. These muscles include:
Why is the core important?
It is important to learn to engage all of the core muscles to create a rigid torso from which you generate force when performing heavy lifts in the gym. The reason planks are not challenging enough is because human movement and lifting in the gym, which are expressions of human movement, require you to generate force from the arms and legs off a fixed torso. When squatting the trunk is held in a rigid and fixed position while the legs are moved into flexion during the descent. Recent research suggests that it's not all that important to engage the core if you were to pick up a pencil off the ground. But when squatting a decent amount of weight, if we don't engage the core then the back will either fault into extension or the chest will cave forward and produce trunk flexion. While it may or may not cause injury, at the very least it is going to create an energy leak. This means that you cannot generate force to your full extent and are leaving pounds on the table, which results in reduced strength and muscular gains. Getting into what exercises are better for core development, there are two key things to incorporate: training all planes of motion and adding movement of the extremities.
Anti-extension refers to resisting the movement of back extension. The plank is the classic example of this type of core training. You have to prevent the hips from dropping to the floor, this backward arching of the back is called extension. Extension is resisted by the muscles in the front of the abdomen. Add a challenge by moving the arms while keeping the body in a straight line. This hand step up plank adds movement from the arms once you master the classic plank.
Anti-flexion is resisting the upper body from bending forward by activating the back extensors. People are often afraid to do direct back training because they're afraid of getting injured, but its actually one of the best things to do. Strength training builds resiliency in our muscles and bones, this does not exclude the back muscles. Isometric exercises (exerting a muscular force without movement at that joint) are a good place to start. This Chinese plank can be done across any two supportive surfaces. Increase difficulty by changing the gap distance, adding weight, or adding a single leg lift.
We challenge our lateral stability in every day life even if you don't realize, which is why it's important for exercises in the gym to translate to every day life. When you carry groceries, a purse, or a bucket in one hand the opposite side of your trunk has to turn on so that you don't tip over. Side planks are another classic exercise, but will quickly become too easy. Also, think about the real life scenarios I just mentioned, what are you doing with your groceries? Just standing there with them? No, you're walking them into your house. This side plank variation adds a leg lift to provide lower extremity movement and a more dynamic core challenge.
The last plane of motion is rotation. The obliques are primarily activated to prevent the trunk from rotating to one side. In this exercise the feet are anchored so the arms can be moved freely. The further the plate is pressed away from the body the more rotational force is applied to the trunk. Keep the body in midline (no side bending) and move slow and controlled. Another good exercise for this is the paloff press.